I will try pulling out the sensors and getting the brakes warm to see if they squeal. what could be the other reasons if not the sensors?

Brake squeel is caused by vibration between the rotors, pads, and calipers. Most of the noise, in my experience, is caused from the calipers clips which hold the pads in place. You can apply some CNC anti-squeel on the back of the pads to see if this helps. You could also have a poor contact between the pads an the rotors, turning the rotors might alleviate the noise. Finally, sometimes the surface of the pads becomes uneven and might need to be sanded down with fine grit sand paper. Due to the material of our brake pads, this is just something you, and every other owner, is going to have to deal with. I found the OEM pads make less noise then the "low dust" pads.